Electron-deficient Naphthalene Diimide Research Articles

Three Semiconductive 1D Naphthalene Diimide/Iodoplumbate Perovskites with High Moisture Tolerance and Long-Lived Charge Separation States.

Low-dimensional inorganic-organic hybrid perovskites with high moisture tolerance and long-lived charge separation states have captured significant attention in the field of optoelectronic devices. To further achieve the relationship between crystal structures and stability, as well as charge separation behaviors, three one-dimensional hybrid perovskites containing electron-deficient naphthalene diimide ammonium (NDIEA) and electron-rich iodoplumbate chains, [(H2NDIEA)Pb2I6]·2DMF (1), [(H2NDIEA)2Pb5I14·(DMF)2]·4DMF (2), and [(HNDIEA)2Pb2I6]·3H2O (3), were synthesized. Crystal structure determinations revealed various synthesis conditions leading to different stacking modes, especially the inorganic lead iodide fraction, which resulted in different water resistances and charge-separated behaviors. The comprehensive analysis found that strong intermolecular interactions (anion-π interactions and π-π interactions), and matching energy levels between protonated NDIEA and iodoplumbate chains, can facilitate the generation of long-lived charge separation states and extraordinary moisture stability, even in the water environment. In addition, the conductivity behavior of 3 was also explored in detail.

Separation of Cyclohexanone and Cyclohexanol by Adaptive Pillar[5]arene Cocrystals Accompanied by Vapochromic Behavior.

The separation of cyclohexanone (CHA-one) and cyclohexanol (CHA-ol) mixtures is of great importance in the chemical industry. Current technology exploits multiple steps of energy-intensive rectification due to their close boiling points. Herein, we report a new and energy-efficient adsorptive separation method employing binary adaptive macrocycle cocrystals (MCCs) built with π-electron-rich pillar[5]arene (P5) and an electron-deficient naphthalenediimide derivative (NDI) that can selectively separate CHA-one from an equimolar CHA-one/CHA-ol mixture with >99% purity. Intriguingly, this adsorptive separation process is accompanied by vapochromic behavior from pink to dark brown. Single-crystal and powder X-ray diffraction analyses reveal that the adsorptive selectivity and vapochromic property are derived from the CHA-one vapor inside the cocrystal lattice voids triggering solid-state structural transformations to yield charge-transfer (CT) cocrystals. Moreover, the reversible transformations make the cocrystalline materials highly recyclable.

Organic nanoparticles with tunable AIE derived from amino acids appended naphthalenediimide based amphiphiles

Fluorescent organic nanoparticles (FONPs) are unique cooperative manifestations of supramolecular self-aggregates and luminescent nanoparticles. In this work, we developed naphthalenediimide (NDI) based amphiphiles (NDI-1-9) having amino acids substitution from L-alanine to L-phenyl alanine to 3-(2-naphthyl)-L-alanine in absence and presence of alkyl spacer (C-6, C-11). Formation of self-aggregated spherical organic nanoparticles of ∼50 nm took place at and above 50 vol% water or methyl cyclohexane (MCH) in different binary solvent systems (DMSO/DMF-water, CHCl3-MCH) via J-aggregation. In case of NDI-1-3 (amino acids are directly connected to the NDI) self-assembled FONPs (MCH in CHCl3) exhibited aggregation-induced emission (AIE) through excimer formation. Red shift in the emission maxima were observed from 484 nm to 495 nm, and 590 nm, respectively with increasing π electron cloud at substituted donor from NDI-1 to NDI-3. Alongside, in case of aromatic amino acids substitution, FONPs of 6-amino caproic acid spacer containing NDI derivatives (NDI-5 and NDI-6) showed AIE at 505 nm and 545 nm (water in DMF/DMSO). Corresponding 11-amino undecanoic acid containing analogues (NDI-8 and NDI-9) showed AIE at 480 nm and 585 nm in CHCl3-MCH and DMF/DMSO-water. The multi colour emission from blue-green to yellow-orange with enrichment of π-electron cloud density in the side chain substitution of NDI was observed possibly due to the facilitated electron transfer at a lesser energy to the electron deficient NDI core that resulted in red shifted emission maxima. This was further clarified by regulating the availability of π-electrons of phenyl ring of NDI-2 by including electron withdrawing –NO2 and donating -OMe groups at the molecular backbone (NDI-2a and NDI-2b) that showed blue shifted (475 nm) and red shifted (570 nm) emission maxima with respect to NDI-2 (495 nm). However, increase in alkyl spacer length between side chain substitution and NDI core yielded relatively lower quantum yield presumably due to the impeded electron transfer.

Thermosalient effect of a naphthalene diimide and tetrachlorocobaltate hybrid and changes of color and magnetic properties by ammonia vapor.

An organic-inorganic hybrid metal halide (OIMH), namely the electron-deficient naphthalene diimide (NDI) and [CoCl4]2- hybrid (1), showed potential as a sensor for ammonia and amines, in addition to magnetic changes upon vapochromism. Crystal 1 exhibited thermosalient behavior such as leaping and movement, at around 130 °C, which could be explained to be associated with the removal of water molecules from the crystal lattice as shown by TGA and DSC. Compound 1 changed from green to black within 5 minutes when exposed to ammonia vapor, which was attributed to the radical formation in the NDI moiety as evidenced by ESR, and this phenomenon was preserved even when other mono- and di-alkylamines were applied. The exposure of 1 to ammonia resulted in a subsequent color alteration, progressing from black to a gradually dark orange after one day (1_NH3_1 day). This transformation was concomitant with the formation of [Co(NH3)6]3+ from [CoCl4]2-, leading to a modification of the magnetic properties from paramagnetic Co(II) (S = 3/2) to diamagnetic Co(III) (S = 0). Based on these findings, compound 1 represents the first example of an OIMH that exhibits thermosalient behaviour, color change, and magnetic conversion upon exposure to ammonia.

Enhancing the Backbone Coplanarity of n-Type Copolymers for Higher Electron Mobility and Stability in Organic Electrochemical Transistors.

Electron-transporting (n-type) conjugated polymers have recently been applied in numerous electrochemical applications, where both ion and electron transport are required. Despite continuous efforts to improve their performance and stability, n-type conjugated polymers with mixed conduction still lag behind their hole-transporting (p-type) counterparts, limiting the functions of electrochemical devices. In this work, we investigate the effect of enhanced backbone coplanarity on the electrochemical activity and mixed ionic-electronic conduction properties of n-type polymers during operation in aqueous media. Through substitution of the widely employed electron-deficient naphthalene diimide (NDI) unit for the core-extended naphthodithiophene diimide (NDTI) units, the resulting polymer shows a more planar backbone with closer packing, leading to an increase in the electron mobility in organic electrochemical transistors (OECTs) by more than two orders of magnitude. The NDTI-based polymer shows a deep-lying lowest unoccupied molecular orbital level, enabling operation of the OECT closer to 0 V vs Ag/AgCl, where fewer parasitic reactions with molecular oxygen occur. Enhancing the backbone coplanarity also leads to a lower affinity toward water uptake during cycling, resulting in improved stability during continuous electrochemical charging and ON–OFF switching relative to the NDI derivative. Furthermore, the NDTI-based polymer also demonstrates near-perfect shelf-life stability over a month-long test, exhibiting a negligible decrease in both the maximum on-current and transconductance. Our results highlight the importance of polymer backbone design for developing stable, high-performing n-type materials with mixed ionic-electronic conduction in aqueous media.

Two-dimensional covalent organic frameworks with spatial-distribution defined D-A structures for efficient near-infrared photothermal conversion

Two naphthalene diimide (NDI) based covalent organic frameworks (COFs) with stable diimide linkages were prepared by a condensation reaction between amine and anhydride. The spatially alternating distribution of electron-deficient NDI and electron-rich triphenylamine or 1,3,5-triphenylbenzene within the two-dimensional plane induces a charge transfer (CT) process resulting in significant near-infrared absorption characteristics. The different electron-donating behaviors led to a change in the photophysical properties and photothermal conversion properties. In addition, the photothermal conversion efficiency of NDI-N-COF with triphenylamine as a donor group reached 77.9%.

Photochromic polyoxometalate/naphthalenediimide hybrid structure with visible-light-driven dye degradation

A feasible method to construction multifunctional hybrid compounds is the incorporation of appropriate functional inorganic and organic components through self-assembly. Naphthalene diimides (NDIs) and polyoxometalates (POMs) are two versatile building blocks that have been used in many fields. In this paper, self-assembly of electron-deficient NDI ligand and POM resulted in an organic-inorganic hybrid compound, [Ce2(BINDI)(DMF)8]·[Mo6O19] (1), (H4BINDI = N, N′-bis(5-isophthalic acid)-1,4,5,8-naphthalene diimide), with segregated Mo6O192− polyanions and two-dimensional cationic coordination network. Because of the photochemical activities of organic and inorganic components, this hybrid compound exhibits interesting reversible photochromic behavior under ultraviolet–visible light irradiation. XRD, EPR, and XPS studies demonstrated that the photochromic behavior resulting from the coaction of NDI and Mo6O192− polyanions. Moreover, this hybrid material shows excellent photocatalytic degradation activity toward the methylene blue (MB) dye under visible light irradiation.

Merging of the photocatalyst decatungstate and naphthalene diimide in a hybrid structure for the oxidative coupling of amines.

Designing and developing novel hybrid materials for the effective photoconversion of organic substrates is of great importance. Crystalline hybrid heterostructures, as an attractive class of material, are composed of semiconducting organic and inorganic components with fast-responsive charge-separated properties and thus they are promising photocatalysts. Naphthalene diimides (NDIs) and decatungstate (W10O324-) are two versatile semiconductor components that have been utilized as building blocks for the construction of functional materials for various applications. In this context, we demonstrated that the combination of an electron-deficient NDI derivative with W10O324- resulted in an organic-inorganic hybrid compound, namely Zn2(DPNDI)(W10O32)(DMA)6 (DPNDI = N,N'-di-(4-pyridyl)-1,4,5,8-naphthalene diimide) (1). Because of consecutive photo-induced electron transfer processes among the components, this hybrid compound exhibits fast-responsive reversible photochromic properties, and it efficiently photocatalytically oxidizes amines to imines under mild conditions with high yields and an excellent substrate application range.

Reversible photochromism and photoresponsive luminescence in naphthalene diimide-based framework with Lindqvist-type polyoxometalate template

Metal-organic frameworks that contain photoactive organic ligands or photoactive inorganic components are an emerging class of multifunctional hybrid materials that in recent years has gradually become an ideal platform for building photochromic complexes. In this paper, a metal-organic framework based on naphthalene diimide (NDI) ligand with Lindqvist-type W6O192– polyanions, [Ce2(BINDI) (DMF)8]·[W6O19] (1), (H4BINDI = N, N'-bis(5-isophthalic acid)-1,4,5,8-naphthalene diimide) was synthesized and systematically characterized. It displays a cationic two-dimensional grid coordination network, featuring anion–π interactions between W6O192– and expanded π–electron deficient naphthalene diimide (NDI) moieties. Moreover, because of the presence of electron-deficient NDI moieties and photoactive W6O192–, this complex exhibits fast responsive reversible photochromism and photoresponsive tunable luminescence. UV–Vis, IR, PXRD, EPR, and XPS spectral studies indicate that the obviously photochromic phenomenon of complex 1 is derived from photoinduced electron-transfer form NDI radicals and W5+ species.

Two photochromic hybrid materials assembled from naphthalene diimide as photocatalysts for the degradation of carcinogenic dye basic red 9 under visible light

• Two electron-transfer hybrid compounds based on electron-deficient naphthalene diimide and polyoxometalate were synthesized and characterized. • Complexes 1 and 2 exhibit the eye-detectable photochromic phenomenon. • Complexes 1 and 2 show good photocatalytic activity for degradation of carcinogenic dye BR9. Naphthalene diimide (NDI) derivatives and polyoxometalates (POMs) are two kinds of functional moieties with very different properties for applications in different fields. Two rare multifunctional inorganic-organic hybrid crystalline materials based on NDI and POM, have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analyses, and thermogravimetric analysis. These compounds show fast responsive reversible photochromic behaviors (within five minutes) under UV–vis light irradiation, which arise from the photoinduced electron transfer production of organic radicals rather than photoinduced isomerization or photolysis. Furthermore, due to presence the redox-active NDI and POMs, these unique hybrid materials are good heterogeneous photocatalyst for the degradation of carcinogenic organic dye basic red 9 (BR9) with a degradation rate of more than 86% within 120 min in the presence of H 2 O 2 under visible light irradiation. This work will provide a new perspective to explore multifunctional hybrid materials with useful photochromic and photocatalytic properties.

Unveiling electron transfer in a supramolecular aggregate for adaptive and autonomous photochromic response

SummaryInteractive and responsive materials are dynamic molecular systems that are capable of modulating their behavior and adapting to environment autonomously. Photochromic materials are among the fascinating class of dynamic responsive systems and widely used in molecular switches and optoelectronic devices. However, the phototriggered color changing largely relies on the conformation transformation of the photochromic motif, which significantly limited their usage in organic liquid solutions. Herein, we demonstrate a photochromic organic supramolecular system by using electron-rich N,N-dimethylacetamide (DMA) and electron-deficient naphthalenediimide (NDI) as a donor and acceptor, respectively. In the binary system, the photo-induced electron transfer through lone pair···π interactions pathway leads to dynamic photochromic response not only in the solution but also in the crystalline aggregated state. Furthermore, by incorporating the supramolecules in the polymer matrix, the transparent polymeric film also exhibits rapid photochromic response, which makes it a promisingly interactive and adaptive photochromic material.

Selective formation of spiroborate-based double-stranded hetero-helicates assisted by donor–acceptor interactions

A novel spiroborate-based double-stranded hetero-helicate is selectively formed through donor–acceptor interactions between the central electron-rich porphyrin and electron-deficient naphthalene diimide units.

Electron-deficient naphthalene diimide directed metal halides with visible light driven photocatalytic properties

Naphthalene diimides (NDIs) are a family of the organic dyes with excellent electron accepting abilities, which have attracted great interest due to their widespread applications in many fields. In this work, a protonated NDI derivative was used with different metal halides to construct two inorganic-organic hybrid compounds, (H2DPMNI)·(Cu4I6)·(CH3CN) (1), and (H2DPMNI)·(Pb2I6)·(DMF) (2) where DPMNI is N,N′-bis(4-pyridylmethyl)-1,4,5,8-naphthalene diimide. These compounds were characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, and thermogravimetric analysis. The structure analysis revealed that the compounds 1 and 2 were built from one-dimensional metal halides attached by protonated DPMNI via C-H···anion and anion-π interactions. Due to the facilitated electron transfers between one-dimensional metal halides and protonated DPMNI components, compounds 1 and 2 exhibited excellent photocatalytic activities for degrading RhB in the presence of visible light radiation. This work provides a new way for the design and synthesis of diverse new types of photocatalytic hybrid materials.

Application of naphthalene diimide in biotechnology

Naphthalene diimide (NDI) is an electron-deficient, robust, and planar molecule. These characteristics make it highly applicable to electronic devices that take advantage of their electric character, for imide group-based supramolecular materials that utilize hydrogen bonding, or for sensing materials with a combination of functional groups. Water-soluble NDI binds to a DNA duplex via the threading intercalation mode. Such NDI has enabled the development of unique DNA analytical techniques, functional DNA polymers, and supramolecular polymers. A ferrocene-containing NDI, possessing electrochemically active sites, has been applied to an electrochemical gene detection system and utilized in the precision analysis of genes and single nucleotide polymorphisms. Recently, a DNA quadruplex was identified as one of the noncanonical DNA structures formed by a guanine quartet (G4). The latter serves as one of the control units of gene expression and is associated with cancer development. A stable complex was formed between electron-deficient NDI and the electron-rich G4 planes. Since the G4 stabilizer is recognized as an anticancer agent with relatively few side effects, NDI derivatives may serve as potential candidates for anticancer therapeutics or for designing a unique cancer-detection system. Water-soluble Naphthalene diimide (NDI) binds to the DNA duplex via threading intercalation mode. This has provided unique DNA analytical techniques, functional DNA polymers, and supramolecular polymers. Especially the ferrocene-containing NDIs, having electrochemically active sites, has been applied to an electrochemical gene detection system and also utilized in the precision analysis of genes and single nucleotide polymorphisms. Recently, NDI derivatives have been recognizing as potential candidate for anticancer therapeutics and for designing a unique cancer-detection system.

Self-healing polyurethane elastomers based on charge-transfer interactions for biomedical applications

One promising application of self-healing polymeric materials is biomedical use. Although charge-transfer (CT) interactions have been employed to construct self-healing polymers as well as other reversible bonds and interactions, their potential for biomedical applications has never been investigated. In this study, we fabricated self-healable and cell-compatible polyurethane elastomers cross-linked by CT complexes between electron-rich pyrene (Py) and electron-deficient naphthalene diimide (NDI) by simply blending two linear polymers with Py or NDI as a repeating unit. The elastomers with different blend ratios self-healed damage over 1 day in mild conditions, including in air and water at 30–100 °C. The mechanical properties of damaged elastomers were almost restored after healing in air at 100 °C, and even in air at 30 °C and in water at 70 °C, healing was also possible to a certain extent. The good cell compatibility of the polyurethane elastomers was demonstrated by culturing two kinds of cells on the thin film substrates. Self-healable and cell-compatible polyurethane elastomers cross-linked by charge-transfer complexes between electron-rich pyrene (Py) and electron-deficient naphthalene diimide (NDI) were fabricated by simply blending two linear polymers with Py or NDI as a repeating unit. The elastomers with different blend ratios self-healed damage over 1 day in mild conditions, including in air and water at 30–100 °C. The good cell compatibility of the polyurethane elastomers was demonstrated by culturing two kinds of cells on the thin film substrates.

A Flexible Interpenetrated Zirconium-Based Metal-Organic Framework with High Affinity toward Ammonia.

Flexible metal-organic frameworks (MOFs) are highly attractive porous crystalline materials presenting structural changes when exposed to external stimuli, the mechanism of which is often difficult to glean, owing to their complex and dynamic nature. Herein, a flexible interpenetrated Zr-MOF, NU-1401, composed of rare 4-connected Zr6 nodes and tetratopic naphthalenediimide (NDI)-based carboxylate linkers, was designed. The intra-framework pore opening deformation and inter-framework motions, when subjected to different solvent molecules, were investigated by single-crystal XRD. The distance and overlap angle between the stacked NDI pairs in the entangled structure could be finely tuned, and the interactions between NDI and solvent molecules led to solvochromism. Furthermore, the presence of electron-deficient NDI units in the linker and acid sites on the node of the interpenetrated porous structure offered high density of adsorption sites for ammonia molecules, resulting in high uptake at low pressures.

Multifunctional naphthalene diimide-based coordination polymers: Photochromism and solventchromism

Naphthalene diimides (NDIs), a class of organic dyes with high photochemical activity and high redox activity, have attracted considerable interest attributing to their photoinduced electron transfer to form stable radical anions upon irradiation in the presence of electron donors. In this study, a naphthalenediimide-based ligand and different aromatic carboxylic acids self-assembled in the presence of zinc ions, forming three novel coordination polymers, [Zn2 (DPMNI) (TPDC)2] (1), [Zn (DPMNI) (BPC)] (2), Zn (DPMNI) (HBTC) (3) (DPMNI = N,N′-bis(4-pyridylmethyl)-1,4,5,8-naphthalene diimide, H2TPDC = thiophene-2,5-dicarboxylic acid, H2BPC = 4,4′-biphenyldicarboxylic acid, H3BTC = 1,3,5-benzenetricarboxylic acid). These coordination polymers characterized by single-crystal X-ray diffraction, elemental analyses, IR spectroscopy, powder X-ray diffraction, and theromgravimetric analysis. Because of the presence of electron-deficient NDI moieties, they exhibit reversible photochromic properties. Furthermore, due to the different π–π interactions between the NDI moieties and aromatic carboxylic acid, compounds 1–3 exhibit different photosensitive properties. Moreover, the solvatochromic behaviour of compound 1 was also investigated.

Fluorescent supramolecular mechanophores based on charge-transfer interactions.

Supramolecular mechanofluorophores based on charge-transfer (CT) interactions between fluorescent pyrene and naphthalene diimide(s) with a tandem structure are newly developed and incorporated into the mid-chain of poly(ε-caprolactone)s. The fluorescence (FL) is quenched by the intramolecular CT interactions even at low concentrations both in solution and in the polymer matrix, and turn-on FL is induced upon application of mechanical forces.

Synthesis of Functionalized Naphthalene Diimides and their Redox Properties

In this article, we have discussed the recently developed synthetic routes to amplify the electron‐poor nature of the naphthalenediimides (NDIs) as well as the integration of electron‐rich donor groups towards ambipolar and strongly electron donating NDIs. Non‐conventional electron withdrawing groups (EWGs) have been applied, leading to highly electron deficient NDIs. Highly π‐acidic molecules with LUMO levels up to –5.0 eV have now been realized. Cationic EWGs have been integrated at the NDI‐core resulting in six‐electron acceptors called “electron‐sponge”. Electron donating groups like tetrathiafulvalene, dicyanomethides, amino‐groups, etc. have been substituted to realize ambipolar NDIs with high HOMO levels and “electron‐reservoir” properties. Diverse coupling reactions such as, Suzuki, Sonogashira, Stille, Buchwald–Hartwig, etc. have been performed to achieve attractive redox properties. Double cross‐coupling reactions have been successful with metallacyclopentadienes to establish highly extended NDIs. The new synthetic routes to NDIs have significantly extended the electrochemical window, improved their optical properties and have resulted in attractive panchromatic systems and driven new applications.

Donor-Acceptor [2]- and [3]Catenanes Assembled from Versatile Pre-Organized Cp*Rh/Ir-Directed Pseudorotaxane Tectons.

A stepwise self-assembly protocol has been used to synthesize [2]- and [3]catenanes. Firstly, binuclear Cp*Rh/Ir-directed (Cp*=pentamethylcyclopentadienyl) pseudorotaxanes were prepared through self-assembly, driven by donor-acceptor interactions between electron-deficient naphthalenediimide (NDI) units and an electron-rich crown ether. Subsequently, the pre-organized pseudorotaxanes were applied as tectons for self-assembly of [2]- and [3]catenanes by combination with very simple linkers. The structures of the catenanes were confirmed by NMR spectroscopy, ESI mass spectrometry, single-crystal X-ray diffraction analysis, and elemental analysis.